Skin-coloring powder mixture

ABSTRACT

The invention related to powder mixtures containing formaldehyde- and/or formic acid-releasing compounds which have skin-tanning properties, which powder mixtures contain an agent which forms sulphite ions and, if appropriate, a stabilizer, and to the preparation and use of these powder mixtures for manufacturing cosmetic or pharmaceutical preparations.

This application is a continuation of Ser. No. 08/234,795 filed Apr. 28,1994 U.S. Pat. No. 5,656,262.

This is a continuation of the application Ser. No. 08/379,986 filed Jan.27, 1995, now U.S. Pat. No. 5,633,409.

BACKGROUND OF THE INVENTION

The invention relates to a powder mixture, containing formaldehyde-and/or formic acid-releasing compounds which have skin-tanningproperties, which powder mixture contains an agent which forms sulphiteions.

It has been known for some time that compounds which have a ketol group

preferably hydroxymethyl ketones, in particular dihydroxyacetone, have aself-tanning effect on human skin. This self-tanning effect isessentially based on a Maillard reaction between the ketol group ofthese compounds and the amino acids of the skin.

The hue obtained in this reaction can be further enhanced by addingcertain adjuvants (for example EP 0 425 324).

Moreover, WO 91/12222 proposes to stabilize dihydroxyacetone (DHA) bycoating at least part of it, in its dimeric form, with awater-impermeable composition. This publication furthermore proposes toemploy formaldehyde-releasing compounds to prevent the bacterialdegradation of DHA.

SUMMARY OF THE INVENTION

It has now been found that compounds, such as, for example, DHA, whichhave a ketol group, slowly release formaldehyde and/or formic acid inthe cosmetic preparations. These are, in general, traces of formaldehydeor formic acid, i.e. formaldehyde contents of a few ppm, as a rule,20-100 ppm.

It was therefore an object of the present invention to find pulverulentcomponents which can be processed to give stable mixtures, in which theformation of formaldehyde and formic acid is completely suppressed.

Surprisingly, it has been found that, using agents which form sulphiteions, e.g., a source of sulfite ions, the formation of formaldehyde andformic acid can be completely suppressed in such pulverulent componentsand in formulations made with them.

The invention therefore relates to a powder mixture containingformaldehyde- and/or formic acid-releasing compounds which haveskin-tanning properties, which powder mixture contains an agent whichforms sulphite ions and, if appropriate, stabilizer.

The invention furthermore relates to the use of such a mixture in themanufacture of cosmetic or pharmaceutical preparations.

The invention furthermore also relates to the preparation of thesemixtures, where at least one of the components, in particular the agentforming sulphite ions, is triturated or coated with the stabilizer.

The following are preferred embodiments:

a) mixtures in which the compound which has skin-tanning properties isdihydroxyacetone;

b) mixtures in which the agent which forms sulphite ions is a hydrogensulphite, disulphite or dithionite, preferably an alkali metal hydrogensulphite, alkaline earth metal hydrogen sulphite, alkali metaldisulphite or alkali metal dithionite, in particular sodium hydrogensulphite, sodium bisulphite or sodium dithionite;

c) mixtures which contain 45 to 99, preferably 80 to 90, % by weight ofa formaldehyde- and/or formic acid-releasing compound (i.e., a compoundwith self-tanning properties), 0.1 to 50, preferably 1 to 20, % byweight of an agent which forms sulphite ions, and 0.1 to 5% by weight ofa stabilizer, e.g., one which prevents the decomposition of theself-tanning compound, as described in WO 91/12222, in each case basedon the total mixture;

d) mixtures in which the ratio by weight between the agent which formssulphite ions and the formaldehyde- and/or formic acid-releasingcompound is greater than 0.01;

e) mixtures which contain, as stabilizer, a stearate, in particularmagnesium stearate;

f) mixtures which contain, as stabilizer, a film-forming agent;

g) mixtures which contain, as stabilizer, a cellulose derivative, inparticular ethylcellulose or nitrocellulose;

h) mixtures which contain, as stabilizer, a higher alcohol, such as, forexample, cetyl alcohol, a paraffin or another, conventional polymericcoating material.

Preferred compounds which have skin-tanning properties are those havinga ketol group

in particular dihydroxyacetone.

Preferred agents which form sulphite ions are metal sulphlites, metaldisulphites or metal hydrogen sulphites and metal dithionites, such as,for example, sodium hydrogen sulphite, calcium hydrogen sulphite, sodiumsulphite, potassium sulphite, sodium dithionite, zinc dithionite andsodium disulphite.

The mixture according to the invention is preferably employed in themanufacture of cosmetic preparations as a composition for tanning thehuman epidermis. Such a composition is in various forms which areconventionally used for this type. For example, it can be, inparticular, in the form of oily or oily/alcoholic lotions, emulsions,such as a cream or a milk, in the form of oily/alcoholic, oily/aqueousor aqueous/alcoholic gels or in the form of solid sticks or elseformulated as an aerosol.

It may contain cosmetic adjuvants which are conventionally used in thistype of composition, such as, for example, thickeners, plasticizers,humectants, surfactants, fungicides, bactericides, preservatives, inparticular alkyl 4-hydroxybenzoates, antifoams, perfumes, waxes,lanolin, propellants, colorants and/or pigments which impart color tothe composition itself, UV filters for the protection against UV-Aand/or UV-B rays and other ingredients customarily used in cosmetology.

It is highly preferred that the preparations according to the inventiondo not contain formaldehyde or formaldehyde-releasing compounds asbactericides.

An oil, wax or other fatty substance, a lower monoalcohol or a lowerpolyol or mixtures of these may be used as solubilizers. Theparticularly preferred monoalcohols or polyols include ethanol,i-propanol, propylene glycol, glycerol and sorbitol.

A preferred embodiment is an emulsion in the form of a cream or milk andincludes, in addition to the skin-tanning compound, fatty alcohols,fatty acid esters, in particular fatty acid triglycerides, fatty acids,lanolin, natural or synthetic oils or waxes and emulsifiers in thepresence of water.

Other preferred embodiments are oily lotions based on natural orsynthetic oils and waxes, lanolin; fatty acid esters, in particularfatty acid triglycerides, or oily/alcoholic lotions based on a loweralcohol, such as ethanol, or a glycol, such as propylene glycol and/or apolyol, such as glycerol, and oils, waxes and fatty acid esters, such asfatty acid triglycerides.

The cosmetic composition can also be in the form of an alcoholic oraqueous gel which includes one or more lower alcohols or lower polyols,such as ethanol, propylene glycol or glycerol, and a thickener, such assilica.

The oily/alcoholic gels additionally contain a natural or synthetic oilor wax.

The solid sticks are composed of natural or synthetic waxes and oils,fatty alcohols, fatty acid esters, lanolin and other fatty substances.

Other suitable compositions are cosmetic sunscreen products whichinclude at least one UV-B and/or UV-A filter.

Examples of suitable UV filters are cinnamic acid derivatives,benzylidenecamphor and its derivatives, p-aminobenzoic acid and itsderivatives, salicylic acid derivatives, benzophenone derivatives anddibenzoylmethane derivatives. As a rule, the preparations contain 0.2 to10% by weight of these UV filters.

If a preparation is formulated as an aerosol, the conventionalpropellants, such as alkanes, fluoroalkanes chlorofluoroalkanes aregenerally used.

If appropriate, the preparation may contain thickeners:

The thickeners or gelling agents known to the person skilled in the artcan be used for thickening, examples being guar gum,heterobiopolysaccharides, xanthan gush scleroglucans, cellulosederivatives, such as, for example, methylcellulose,hydroxyethylcellulose, hydroxymethylpropylcellulose, alkali metal saltsof carboxymetbylcellulose, and polyacrylic acids.

The mixtures according to the invention can be prepared big a range ofprocesses known per se to the expert. This is because it has emerged,surprisingly, that all that is necessary for achieving a stabilizingeffect is that contact between the individual components of the powder,i.e., the compound with self-tanning properties and/or the source ofsulfite ions, is not too intimate.

Suitable stabilizers are therefore, for example, conventionallubricants, such as, for example, stearates, with which at least one ofthe powder components is triturated or ground. The at least partialcoverage of the surface of the powder component, the self-tanningcompound or the sulfite ion source, with the stabilizer achieved in thisprocess suffices for the stabilization required. This trituration of thepowder component with a lubricant can be carried out in conventionaldevices and mixers which are known to a person skilled in the art.

However, other agents which can be used for the stabilization are allconventional film-forming agents, such as, for example, cellulosederivatives, higher alcohols, paraffins and polymers. These agents areconventionally dissolved in a suitable solvent. Granules which can thenbe mixed with the second component are obtained by making the powdercomponent into a paste together with the solution and subsequentlydrying and screening the product. However, it is also possible to spray,in a mixer, the powder component with the solution of the film-formingagent and drying the product, or other processes known to a personskilled in the art can be used.

It is preferred that at least one of the powder components is treatedwith the stabilizer. The question of which of the two components is tobe treated can be decided by a person skilled in the art from apractical point of view, for example according to which component can betreated more easily in conventional mixers or granulating devices. Ofcourse, it is also possible to treat both powder components.

In the foregoing and in the following examples, all temperatures are setforth uncorrected in degrees Celsius; and, unless otherwise indicated,all parts and percentages are by weight.

The entire disclosure of all applications, patents and publications,cited above and below, and of corresponding German application No. P 4314 083.1, filed Apr. 29, 1993 is hereby incorporated by reference.

EXAMPLES Example 1

In a mixer, 10 g of sodium sulphite are triturated vigorously with 0.5 gof magnesium stearate, and subsequently mixed with 89.5 g ofdihydroxyacetone. This gives a storage-stable powder mixture which canbe employed immediately for the manufacture of cosmetic preparations.

Example 2

The procedure is analogous to Example 1, but sodium disulphite is usedin place of sodium sulphite.

Examples 3 and 4

The procedure is analogous to Examples 1 and 2, but calcium stearate isused in place of magnesium stearate.

Example 5

98 g of dihydroxyacetone and a solution of 2 g of ethylcellulose in 50ml of ethanol are made into a paste, and this is dried and screened andsubsequently mixed with 10 g of sodium sulphite.

Example 6

The procedure is analogous to Example 5, but sodium disulphite is usedin place of sodium sulphite.

Examples 7-12

The procedure is analogous to Examples 5 or 6, but nitrocellulose, cetylalcohol and paraffin, respectively, are employed in place ofethylcellulose.

Use Example A Self-tanning cream (O/W) % A Emulsifier E 2155 (2) 8.0Liquid paraffin (Article No. 7162) (1) 12.0 Pourable paraffin (ArticleNo. 7158) (1) 2.0 Miglyol 812 (3) 3.0 Isopropyl myristate (4) 2.0 B1,2-propanediol (Article No. 7478) (1) 4.0 Liquid Karion F (Article No.2993) (1) 2.0 Preservative q.s. Demineralized water to 100.0 C DHApowder prepared as described in Example 1 (1) 5.0 Demineralized water2.0

Preparation

Heat phase A to 75° C. and phase B to 80° C. slowly stir phase B intophase A. Cool while stirring, add phase C when the mixture has reached40° C.

Note

The samples contain

0.05% of propyl 4-hydroxybenzoate (Merck Article No. 7427) and

0.15% of methyl 4-hydroxybenzoate (Merck Article No. 6757)

as preservatives.

Suppliers

1. E. Merck, Darmstadt

2. Th. Goldschmidt, Essen

3. Hüls Troisdorf AG, Witten

4. Henkel, Düsseldorf

Use Example B Self-tanning milk (O/W) % A Arlatone 983 S (2) 1.50Arlatone 985 (2) 2.20 Brij 76 (2) 1.50 Liquid paraffin (Article No.7162) (1) 5.00 Miglyol 812 (3) 5.00 B Liquid Karion F (Article No. 2993)(1) 2.50 1,2-propanediol (Article No. 7478) (1) 2.50 Preservative (1)q.s. Demineralized water to 100.00 C DHA powder prepared as described(1) 5.50 in Example 2 Demineralized water 14.50

Preparation

Heal phase A to 75° C. and phase B to 80° C. Slowly stir phase B intophase A. Homogenize. Cool with stirring, add phase C when mixture hasreached 40° C.

Note

Viscosity 14,000 mPas (Brookfield RVT, Sp. C 10 rpm) at 23° C.

The samples contain

0.05% of propyl 4-hydroxybenzoate (Merck Article No. 7427) and

0.15% of methyl 4-hydroxybenzoate (Merck Article No. 6757)

as preservatives.

Suppliers

1. E. Merck, Darmstadt

2. ICI, Essen

3. Hüls Troisdorf AG, Witten

Use Example C Self-tanning milk (W/O) % A Arlacel 481 (2) 3.15 Arlacel989 (2) 3.85 Low-viscosity paraffin (Article (1) 16.00 No. 7174)Isopropyl myristate (3) 3.50 Miglyol 812 (4) 3.50 B 1,2-Propanediol(Article No. 7478) (1) 3.50 Magnesium sulphate heptahydrate (Article No.5882) (1) 0.70 Preservative (1) q.s. Demineralized water to 100.00 C DHApowder prepared as described (1) 5.50 in Example 1

Preparation

Heat phases A and B to 75° C. To avoid heat stress of the DHA powder byprolonged heating, phase C is dissolved in phase B and the solution isstirred into phase A. Homogenize. Cool rapidly with stirring to 25° C.

Note

The samples contain

0.05% of propyl 4-hydroxybenzoate (Merck Article No. 7427) and

0.15% of methyl 4-hydroxybenzoate (Merck Article No. 6757)

as preservatives.

Suppliers

(1) E. Merck, Darmstadt

(2) ICI, Essen

(3) Henkel, Düsseldorf

(4) Hüls Troisdorf AG, Witten

Use Example D Self-tanning cream (O/W) % A Lanette N (2) 15.00 Cetylalcohol (Article No. 989) (1) 2.00 Cetyl palmitate (Article No. (1) 5.0015419) Corona lanolin (3) 0.50 Cetiol (2) 5.00 Petroleum jelly (4) 3.00Oxynex 2004 (Article No. 6940) (1) 0.05 B Liquid Karion F (Article No.2993) (1) 3.00 Preservative q.s. Demineralized water to 100.00 C DHApowder prepared as described (1) 5.50 in Example 3 Demineralized water14.50

Preparation

Heat phase A to 75° C. and phase B to 80° C. Slowly stir phase B intophase A. Homogenize. Cool with stirring, add phase C when mixture hasreached 40° C. and, if appropriate, perfume.

Note

The samples contain

0.05% of propyl 4-hydroxybenzoate (Merck Article No. 7427) and

0.15% of methyl 4-hydroxybenzoate (Merck Article No. 6757)

as preservatives.

Suppliers

(1) E. Merck, Darmstadt

(2) Henkel, Düsseldorf

(3) Croda, Nettertal

(4) E. Wagner, Bremen

Use Example E Self-tanning cream (O/W) % A Arlacel 165 (2) 6.60 AtlasG-1790 (2) 3.60 Lanette O (3) 3.00 Liquid paraffin (Article No. 7162)(1) 1.50 Isopropyl myristate (3) 4.00 Abil AV 200 (4) 1.00 Oxynex 2004(Article No. 6940) (1) 0.05 B Liquid Karion F (Article No. 2993) (1)6.00 Preservative q.s. Demineralized water to 100.00 C DHA powderprepared as described (1) 5.50 in Example 4 Demineralized water 14.50

Preparation

Heat phase A to 75° C. and phase B to 80° C. Slowly stir phase B intophase A. Homogenize. Cool while stirring, add phase C when the mixturehas reached 40° C. and, if appropriate, perfume.

Note

The samples contain

0.05% of propyl 4-hydroxybenzoate (Merck Article No. 7427) and

0.15% of methyl 4-hydroxybenzoate (Merck Article No. 6757)

as preservatives.

Suppliers

(1) E. Merck, Darmstadt

(2) ICI, Essen

(3) Henkel, Düsseldorf

(4) Th. Goldschmidt, Essen

Use Example F Self-tanning gel (aqueous) % A DHA powder prepared asdescribed (1) 5.50 in Example 1 Liquid Karion F (Article No. 2993) (1)2.50 1,2-Propanediol (Article No. 7478) (1) 2.50 Preservative q.s.Demineralized water to 100.00 B Natrosol 250 HHR (2) 1.50 Demineralizedwater 60.00

Preparation

To prepare phase B, Natrosol is slowly added to the eddy of thevigorously stirred water. The addition is effected slowly and uniformlyso that the particles can be distributed in water without lumps beingformed. To prepare phase A, the DRA powder is stirred into the water,and the remaining raw materials are added, with stirring. Thissuspension is stirred into phase B, and the mixture is homogenized.

Note

Slightly opaque gel

The samples contain

0.20% of methyl 4-hydroxybenzoate (Merck Article No. 6757) aspreservative.

Storage at room temperature is recommended to avoid a reduction inviscosity from approximately 40° C.

Suppliers

(1) E. Merck, Darmstadt

(2) Aqualon, Düsseldorf

In the formulations described in Use Examples A to F, no formaldehydewas detected after prolonged storage even at elevated temperature.

Comparison Example 1

A self-tanning cream (O/W) which corresponds to Use Example A isprepared, but in which the DHA powder according to the invention isreplaced by:

a) pure DHA 5.00 g, or

b) DHA coated in accordance with WO91/12222 5.00 g

After storage for 3 months at 40° C., the following concentrations offormaldehyde and formic acid are found:

HCHO (ppm) HCOOH (ppm) Use Example A n.d. n.d. a) 70 3569 b) 70 5825

Comparison Example 2

A self-tanning milk (W/O) which corresponds to Use Example C isprepared, but in which the DHA powder according to the invention isreplaced by:

a) pure DHA 5.00 g, or

b) DEA coated in accordance with WO91/12222 5.00 g

After storage for 3 months at 40° C., the following concentrations offormaldehyde and formic acid are found:

HCHO (ppm) HCOOH (ppm) Use Example C n.d. n.d. a) 33 3438 b) 23 2365

The preceding examples can be repeated with similar success bysubstituting the generically or specifically described reactants and/oroperating conditions of this invention for those used in the precedingexamples.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention and, withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

What is claimed is:
 1. A powder mixture comprising a compound havingskin-tanning properties and releasing at least one of formaldehyde orformic acid a source of sulphite ions and, optionally, a stabilizer. 2.A mixture according to claim 1, wherein the compound having skin-tanningproperties contains a ketol group of the formula


3. A mixture according to claim 2, wherein the compound which hasskin-tanning properties is dihydroxyacetone.
 4. A mixture according toclaim 1, wherein the source of sulphite ions is a hydrogen sulphite,disulphite or dithionite.
 5. A mixture according to claim 4, wherein thesource of sulphite ions is an alkali metal hydrogen sulphite, analkaline earth metal hydrogen sulphite, an alkali metal disulphite organalkali metal dithionite.
 6. A mixture according to claim 5, wherein thesource of sulphite ions is sodium hydrogen sulphite, sodium disulphiteor sodium dithionite.
 7. A mixture according to claim 1, furthercomprising a stabilizer, which is a stearate.
 8. A mixture according toclaim 1, further comprising a stabilizer, which is a cellulosederivative.
 9. A mixture according to claim 1, further comprising astabilizer, which is a polymer.
 10. A mixture according to claim 1,comprising 45-99% by weight, of the compound having skin-tanningproperties, 0.1 to 50% by weight, of the source of sulphite ions, and0.1 to 5% by weight of the stabilizer.
 11. A mixture according to claim1, comprising 80-90% by weight, of the compound having skin-tanningproperties, 1-20% by weight, of the source of sulphite ions, and 0.1 to5% by weight of the stabilizer.
 12. In a self-tanning composition, whichhas skin-tanning properties when applied to the skin, said compositioncomprising a formaldehyde and/or formic acid releasing compound, andconventional adjuvants, the improvement wherein the composition furthercomprises an agent which forms sulphite ions in the composition.
 13. Amixture according to claim 1, produced by a process comprisingtriturating, grinding together or partially coating the compound havingskin-tanning properties, the source of sulfite ions, or both, with thestabilizer.
 14. A mixture according to claim 1, producible by a processcomprising triturating, grinding together or partially coating thecompound having skin-tanning properties, the source of sulfite ions, orboth, with the stabilizer.
 15. A mixture according to claim 13, whereinthe source of sulphite ion is coated.
 16. A mixture according to claim13, producible by a process comprising triturating the compound havingskin-tanning properties, the source of sulfite ions, or both, with aconventional lubricant.
 17. A mixture according to claim 13, producibleby a process comprising partially coating the compound havingskin-tanning properties, the source of sulfite ions, or both, with aconventional film-forming agent or polymer.